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Perceptual Mechanisms in Music Processing
recognized as either a triad (C E G) or a dominant seventh chord, (C E G B ), it may be coded as a perceptual chunk and thus result in a musical percept. The second type of fragment contained the tone F (which does not belong to the scale of F major) followed by a G. This suggested the mechanism of anchoring discussed earlier, whereby the F is linked to the G. The operation of the mechanisms of chord recognition and anchoring in the perception of the tone series F G C B is schematically displayed in Figure 2. PRESENT INVESTIGATION
In the experiments reported next, we have examined to what extent the two hypothetical perceptual mechanisms, chord recognition and anchoring, can explain the perception of a set of tone series. In addition, we wanted to obtain a detailed insight into the mental representations and the expectations that listeners develop while listening to tone series.
Experiment 1 The main purpose of this experiment was to determine to what extent chord recognition and anchoring can explain the perception of brief tone series derived from the collection C4 E4 F 4 G4 B 4 presented in the context of F major. In particular, we tested the following hypotheses: (1) fragments containing only chord tones will be rated highest because the mechanism of chord recognition can be applied; (2) fragments containing an F followed by a G (either immediately or with intermediate tones) will be rated lower, because two mechanisms (chord recognition and anchoring) must be applied.1
Fragment size
Input
Process(es)
3
F GC
Anchoring
4
F GCB
Chord recognition Chord recognition
Percept
F GC {G C} ® fifth or C triad {G C B } ® C7
Fig. 2. Hypothetical operation of the perceptual mechanisms chord recognition and anchoring in the incremental processing of the tone series F G C B . Upon hearing the fragment F G C, the F is anchored to G and G C is recognized as a chord. When subsequently the B is added, the tones G C and B are recognized as C7. 1. The rationale for this hypothesis is that more perceptual effort is needed if two mechanisms must be applied rather than just one: these two perceptual mechanisms must be activated by specific features of the stimulus. The chord recognition mechanism must be put on hold when a nonchord tone occurs. Thus the listener must try harder to “understand” the sequence, which is reflected in a lower goodness rating.